gear rack for Machine Tool Industry

After completion of one or two teeth, the blank and gear rack for Machine Tool Industry cutter stop feeding and the cutter is withdrawn and indexed back to its starting position, thus allowing a short rack cutter of a practical duration to be used. Cutter is once again fed back to depth and routine is repeated. Amount of teeth is managed by the device gearing, and pitch and pressure position by the rack cutter. This method can be used for generation of external spur gears, being ideally suited for cutting large, dual helical gears. For creating helical the teeth, the cutter slides are inclined at the gear tooth helix angle.
The hob is fed into the gear blank to the correct depth and both are rotated together as if in mesh. The teeth of the hob cut in to the work piece in successive purchase and each in a slightly different position. Each hob tooth cuts its profile depending on the shape of cutter , but the accumulation of these straight cuts creates a curved kind of the gear teeth, hence the name generating process. One rotation of the task completes the slicing upto specific depth upto which hob is fed unless the gear includes a wide face.

This methodis specially adopted to cutting large teeth which are challenging to cut by formed cutter, and to cut bevel-gear teeth. It is not widely used at the moment.
In gear planing process, the cutter contains accurate involute rack which reciprocates across the face of the blank and the blank rotates in the right relationship to the longitudinal movement of the cutter as though both roll with each other as a rack and pinion. Initially the cutter can be fed into full tooth depth with cutter reciprocating and blank stationary. Involute form is generated as the blank rotates and involute rack cutter feeds longitudinally.

In the other method, both roughening and completing cuts are taken with single pointed tools. The use of the formed device for finishing is usually impracticable for the bigger pitches which are finished by an individual pointed tool. The amount of cuts required is dependent upon the size of the tooth, quantity of stock to be taken out, and the kind of material.